This invention relates to systems for first combining a gas, such as ozone, with a liquid, such as water, for treating the liquid with the gas, and then removing residual gas from the liquid prior to using the liquid.
The Background of the Invention in my U.S. Pat. No. 5,865,995, granted Feb. 2, 1999, and entitled System For Treating Liquids With A Gas, and in my U.S. patent application Ser. No. 08/071,249, entitled System For Re-circulating A Gas Mixture To Treat Liquids, now U.S. Pat. No. 6,054,046, granted Apr. 25, 2000 are hereby incorporated into this Background of the Invention.
In the systems of my prior patents, a gas, such as ozone, is introduced into a liquid, such as water, and the gas/liquid mixture is caused to flow downwardly as a helical current through an outer chamber of a contact tank, to a lower end of the contact tank, and then back up through a center tube that extends upwardly from a lower region of the contact tank to an outlet conduit at the upper end of the contact tank. In the system of U.S. Pat. No. 5,865,995, the gas is introduced into a stream of untreated liquid and then the mixture is introduced into the contact tank. In the system of my second patent, some of a gas/liquid mixture in the contact tank is re-circulated and new gas is introduced into the re-circulated mixture. Also, new untreated liquid is introduced by itself into the upper end of the contact tank.
An object of the present invention is to improve on the prior systems for the purpose of more efficiently mixing the gas and liquids and more efficiently removing the residual gas following the treatment.
Another object of the present invention is to provide an apparatus for treating liquid with a gas that is relatively small for its capacity, is simple in its construction and is composed of parts that are relatively easy to assemble and disassemble.
The apparatus of the present invention is for treating a liquid with a gas. It is basically characterized by a vertical outer housing having a sidewall, a top end wall and a bottom end wall, and a vertical inner housing within the outer housing, having a sidewall, a bottom wall and an open top spaced downwardly from the top wall of the outer housing. An outer chamber is formed by and between the sidewalls of the inner and outer housings when they are assembled. An inner chamber is formed within the inner housing. A transfer passageway leads from the upper end of the outer chamber into the upper end of the inner chamber. This transfer passageway is formed by and between the top wall of the outer housing and an upper end portion of the sidewall of the inner housing.
According to an aspect of the invention, a gas/liquid mixture is introduced into a lower portion of the outer chamber in such a way that it forms an upwardly flowing helical current in the outer chamber. A gas removal outlet is provided in the inner chamber, radially inwardly of and axially below the passageway at the top of the inner housing that connects the outer chamber with the inner chamber. A liquid outlet conduit is provided below the bottom wall of the inner housing. An outlet in the bottom wall of the inner housing connects the lower end of with the inner chamber to the outlet conduit.
According to another aspect of the invention, the outer housing has an upper portion that includes the top wall and at least a major portion of the sidewall of the outer housing. It also includes a lower portion that includes the bottom end wall of the outer housing. The upper and lower portions of the outer housing are detachably connected together.
According to a further aspect of the invention, the lower portion of the outer housing is formed to include an inlet chamber. The gas/liquid inlet conduit is directed to discharge at a tangent into the inlet chamber. The lower portion of the outer housing may also include the outlet conduit.
According to yet another aspect of the invention, the upper portion of the outer housing includes a first, major portion of the sidewall of the outer housing. The lower portion of the outer housing includes a second, minor portion of the sidewall of the outer housing. A screw connection is provided for detachably connecting the upper and lower sidewall portions of the outer housing.
According to another aspect of the invention, the outlet conduit includes an effluent branch leading away from the apparatus and a re-circulating branch. The apparatus further includes a re-circulating pump having an inlet and an outlet. A conduit connects the re-circulated branch of the outlet conduit with the inlet of the re-circulating pump. Another conduit connects the outlet of the re-circulating pump with a gas and liquid mixing region.
Preferably, a new gas delivery conduit leads into the conduit that extends from the outlet of the pump to the gas and liquid mixing region, for introducing new gas into the re-circulated mixture. Preferably also, an untreated liquid conduit leads to the gas and liquid mixing region. As a result, re-circulated gas/liquid mixture, new gas and untreated liquid are all combined in the gas and liquid mixing region to form a gas/liquid mixture that is then delivered through the gas/liquid inlet conduit into a lower portion of the outer chamber.
In preferred form, an ejector is provided in the re-circulated gas/liquid conduit. Flow of the re-circulated gas/liquid mixture through the ejector draws in some new gas that is added to and is mixed with the re-circulated gas/liquid flow.
In preferred form, a conduit is provided for delivering untreated liquid to the gas and liquid mixing region. As a result, re-circulated gas/liquid mixture, new gas and untreated liquid are all admixed together in the gas/liquid mixing region, to form a mixture that is delivered into the gas/liquid inlet conduit leading into the base of the outer chamber.
According to a still further aspect of the invention, a gas-vent housing is connected to the top end wall of the outer housing. This gas-vent housing extends downwardly from the top end wall into the inner chamber. The gas-vent housing has a sidewall that is spaced radially inwardly from an upper portion of the sidewall of the inner housing. It also has a bottom wall and the gas removal outlet includes one or more openings in this bottom wall. Preferably, the gas-vent housing includes a passageway leading from the one or more openings in its bottom wall, up through the gas-vent housing, and on out through an exhaust opening. The gas-vent housing is provided with a float controlled valve in this passageway which is normally open but is adapted to be closed by the float in response to liquid from the inner chamber rising in the gas-vent housing to a predetermined level. The rising liquid lifts the float and closes a valve in the gas-vent passageway.
The present invention may further includes positioning a filter in the housing for filtering the liquid as it flows through the inner housing to the outlet and the outlet conduit. Preferably, a back wash conduit is provided for leading back wash liquid into the outlet conduit and then through the outlet in the bottom wall of the inner housing. A back wash liquid discharge conduit is connected to the gas/liquid inlet conduit. This discharge conduit is provided with a valve that is normally closed but is opened when a back wash is being performed.
According to an aspect of the invention flow through the outer chamber may be in an downward direction and reverse flow through the inner chamber may be in an upward direction, through a filter medium, and residual gas may be removed from the top of the apparatus and the treated liquid may be removed from the top of the apparatus.
The present invention increases both gas exposure to the liquid and contact time between the liquid and the treatment gas and provides efficient gas removal from the liquid after the treatment. Many other advantages and attributes of the invention will be apparent from the following description of the inventor""s best mode for carrying out the invention, and from the claims and from the various figures of the drawing, all of which provide a disclosure of the principles that make up the present invention.